Conventionally, a recoil starter is used with a manually started internal combustion engine, such as a small two-stroke engine, for example. A pulley is provided with a rope wound thereon. During a starting procedure, a handle attached to the distal end of the rope is pulled such that a ratchet and/or clutch mechanism couples the pulley to the flywheel and crankshaft. Continued pulling of the handle allows transmission of rotational energy to a flywheel and crankshaft to facilitate reciprocation of the piston within the piston cylinder. Rotation of the crankshaft drives a piston and helps provide fuel for ignition. Rotation of the flywheel causes a magneto to power a spark plug, creating a spark for ignition of the engine fuel.
In operating such a starter mechanism, abrupt changes in the engine torque may occur due to piston compression of an air/fuel mixture in the piston cylinder. Such abrupt changes can contribute to uneven, jarring, and/or kickback forces when pulling the handle during the starting procedure. These forces can inhibit engine ignition, generate damaging stresses within certain engine components, and the like.
To reduce these fluctuations in pulling force, conventional starter mechanisms are known to include a second rotating member coupled to the pulley by way of a spring. The second rotating member engages with the engine crankshaft, typically using a ratchet mechanism, for transmission of rotational energy. Rotational energy stored within the spring can be used to assist in transmitting a rotational force to the engine crankshaft during periods of higher required torque. Storing rotational energy within the spring can beneficially dampen the pulling force required by the operator and smooth the starting operation. Such a system can be referred to as a buffered recoil system.
Despite this modification, drawbacks in the typical buffered recoil starter systems remain. There is a need to provide a starter device that utilizes a spring to enable starting the engine with a reduced pulling force, while at the same time reducing the inevitable stresses on components of the spring to provide greater durability and reliability.